Recently, tires for heavy loads mounted on trucks, buses, and the like are able to retain the shape of the tread portion due to the tires having a low aspect ratio on the one hand and due to the disposition of a circumferential reinforcing layer in the belt layer on the other hand. The circumferential reinforcing layer is a belt ply having a belt angle that is substantially 0° with respect to the tire circumferential direction, and is disposed so as to be laminated upon a pair of cross belts. The technologies disclosed in Japanese Patent Nos. 4642760B, 4663638B and 4663639B are conventional pneumatic tires that are configured in this manner. There is a problem with the pneumatic tire in that improvement in wet performance is expected.